Hormonal signaling cascades required for phototaxis switch in wandering Leptinotarsa decemlineata larvae

• DOI: 10.1371/journal.pgen.1007423
• Publication Date: 2019-01-08T01:21:52Z
• Authors: Qing-Wei Meng; Qing-Yu Xu; Tao-Tao Zhu; Lin Jin; Kai-Yun Fu; Wen-Chao Guo; Guo-Qing Li
• Keywords: Phototaxis; Leptinotarsa

Many animals exploit several niches sequentially during their life cycles, a fitness referred to as ontogenetic niche shift (ONS). To successfully accomplish ONS, transition between development stages is often coupled with changes in one or more primitive, instinctive behaviors. Yet, the underlining molecular mechanisms remain elusive. We show here that Leptinotarsa decemlineata larvae finish ONS at wandering stage by leaving plant and pupating soil. At middle phase, also switch phototactic behavior, from photophilic foraging period photophobic. find enhancement of juvenile hormone (JH) signal delays switch, vise verse. Moreover, RNA interference (RNAi)-aided knockdown LdPTTH (prothoracicotropic gene) LdTorso (PTTH receptor impairs avoidance response light, phenotype nonrescuable 20-hydroxyecdysone. Consequently, RNAi beetles pupate soil surface shallow layer soil, most them failing construct pupation chambers. Furthermore, combination depletion LdPTTH/LdTorso disturbance JH causes no additive effects on light site selection. Finally, we establish TrpA1 (transient potential (TRP) cation channel) necessary for acting downstream PTTH. conclude JH/PTTH cascade concomitantly regulates metamorphosis phototaxis drive into start immobile pupal stage.